Investigation of interlaminar toughening properties in carbon fiber composites using wet veil formation of short‐cut aramid fibers

Abstract The application of carbon fiber reinforced polymer (CFRP) in aerospace, automotive and other fields is expanding rapidly due to its high strength‐to‐weight ratio and excellent mechanical properties. However, the susceptibility to delamination damage in the thickness direction still needs to be addressed urgently. In this study, carbon fiber prepregs were combined with short‐cut aramid fiber (SAFs) veils through hot compression molding to produce SAFs‐interlaminar‐toughened carbon fiber reinforced polymer (SAFs‐CFRP). The effect of the areal density of the SAFs on mechanical properties and model II interlaminar fracture toughness (IFT) was investigated. The results demonstrate that at a fiber areal density of 15 g/m 2 , tensile and flexural strengths increased by 33.96% and 34.39%, respectively, compared to the untoughened specimens. Additionally, model II IFT improved by 108.05%, reaching 9.05 KJ/m 2 , a significant enhancement over the untoughened specimens. Cross‐sectional fracture analysis revealed that the toughening mechanism involved fiber bridging, fiber pull‐out, fiber breakage, and fiber debonding of the SAFs within the resin‐rich layers. These processes effectively hinder crack propagation and absorb energy, contributing to the enhancements in toughness and mechanical strength. This study provides a comprehensive framework for interlaminar toughening using SAFs, addressing the critical challenge of delamination and paving the way for CFRP materials with enhanced performance and reliability in advanced engineering applications. Highlights Effective CFRP interlayer toughening was achieved using wet veil‐formed SAFs. The model II IFT of CFRP was significantly increased by 108.05%. The tensile and flexural properties of CFRP were also enhanced.